The present invention relates to an improved audio headphone, and more particularly to a headphone arrangement including amplification means in the signal path to one speaker in each of the headphones, and an improved method of using multi-speaker headphones.
Quadraphonic or four-channel headphones are well-known. References which show particular embodiments of such devices are U.S. Pat. No. 3,984,885, issued to Yoshimura, et al on Oct. 12, 1976 and U.S. Pat. No. 3,927,262, issued to Goeckel on Dec. 16, 1975. Generally speaking, such devices comprise an earpiece or headphone for each ear in which is contained at least two separate speakers. The purpose of such headphones is to reproduce quadraphonically recorded information such as music with the overall purpose being of more realistically recording and reproducing sound. The above-referenced patents and the references cited therein generally relate to improvements in such headphones which are intended to avoid the problem generally encountered in headphones in which the source of the sound appears to the listener to be in the center of his head.
Studio musicians are, of course, quite skilled in the art of quadraphonic sound recording and reproduction. Such musicians often use such equipment for listening to a pre-recorded track while simultaneously playing their own instrument as a practice aid. Of course, if a musician is using headphones which tend to block out the sound of his own instrument, he must typically feed the output of his instrument to an electronic mixing network which then electronically combines the recorded soundtrack with the output of his instrument and then couples the mixed output with sufficient power to his headphones so that he is able to compare the prerecorded signal with that which he is generating. Similar equipment is used in the process of overdubbing or re-recording in which a musician performs a particular musical composition a number of times with the same or different instruments with each performance recorded over that previously performed. It is, of course, necessary in such practice that the musician be able to listen simultaneously to the prerecorded track and to his presently performed music.
It can be seen that relatively expensive equipment has been required for such practice track-making, re-recording, etc., since typically studio quadraphonic or stereophonic mixing and amplification equipment has been used to provide the combined signals to the musician's headphones. It can also be seen that in the process of electronically mixing prerecorded presently produced sounds, the user of the headphones receives both signals and from precisely the same source, thus, reducing his ability to distinguish between the two.
Such typical studio practices would also be quite useful for home or classroom practice and teaching. But since the studio equipment is quite expensive, it is not practical for most musicians, especially students, to use the studio methods. The usual practice methods have involved simply playing a recorded selection through standard amplifiers and loud speakers while the musician plays his instrument through separate amplifiers and speakers. In a classroom situation, an instructor may be providing the original audio signal while the students play along trying to compare their performance to the instructor's. In either of these situations, the musicians have the problem, magnified by modern amplifiers, that their practice is a nuisance to others. In addition, if more than one musician tries to practice at the same time, each has trouble distinquishing his individual performance from the others. An instructor would likewise have trouble isolating a particular student's performance from the others.
Thus, it is seen that there is a need for an inexpensive practice aid which allows musicians to listen to two distinct audio signals at the same time for comparison purposes. In addition, the practice aid should isolate the audio signals from the surroundings and isolate the user of the aid from audio signals, other than the two desired signals.